The present invention is related to aircraft environmental control systems, and in particular to a system and method for detecting contamination of heat exchangers within environmental control systems.
Aircraft often include air conditioning “packs” that, among other things, provide conditioned air for the aircraft. These aircraft may also include one or more ram air fans that draw air through the air conditioning packs while the aircraft is grounded. In many systems, the ram air fan draws air through heat exchangers, which are used to cool air from an aircraft compressed air source, such as a cabin air compressor, for example. Contaminants from the ambient air, as well as larger debris, may cause blockage of the heat exchanger, affecting the air flow through the fan and heat exchangers. Significant heat exchanger contamination can reduce the airflow enough that the ram air fan may operate in an unstable operating mode which may lead to excessive blade stress and in turn, failure of the ram air fan.